1. Field of Invention
The present invention relates to an adjustment mechanism for altering a height of a baby playpen from the ground to a bottom of the baby playpen.
2. Description of Related Art
A baby playpen is a carrier which can provide a confined space for a baby to play therein, and is often used outdoors. For carrying convenience, most of the baby playpens have the developed and folded states. A basic structure of a conventional baby playpen includes a foldable skeleton, a woven fabric and a mattress, wherein the foldable skeleton is formed by connecting a plurality of poles, and the woven fabric is put on the foldable skeleton to form an accommodation space with a bottom and four sides. Since the woven fabric is usually a thin layer fixed on the connected foldable skeleton and fails to support a baby, it is necessary to place a mattress on the bottom to support the baby. Since the woven fabric is fixed on the skeleton and there are a certain height between a bottom of the woven fabric and a top edge of the skeleton, it is difficult for a baby sitter to hold a baby who still cannot stand up from the mattress. Thus, most of the baby playpens in the market have a three-layer mattress. However, the use of the three-layer mattress not only increases the volume of transported material but also increases the manufacturing cost. China Patent No. ZL200820177109.2 discloses a baby playpen including a woven fabric which is disposed around the accommodation space constructed by a skeleton, a mattress which is a foldable mattress placed on the bottom of the accommodation space, wherein the side of the bottom of the accommodation space has engagement portions with which struts are engaged. This conventional baby playpen advantageously uses the effect of conveniently folding the mattress and the function of supporting the mattress by using the struts disposed on the bottom of the playpen. However, this conventional baby playpen has the disadvantages of failing to alter the height of the mattress from the ground, and thus is inconveniently used by different children.